Organic-inorganic hybrid materials. II. Chain mobility and stability of polysiloxaneimide-silica hybrids

Wu, Kuo‐Hui; Chang, T. C.; Yang, Jen‐Chang; Chen, H. B.

doi:10.1002/1097-4628(20010207)79:6<965::aid-app20>3.0.co;2-g

Cited by 17 publications

(9 citation statements)

References 29 publications

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“…Polyimides are typically reinforced with silica via in-situ sol−gel methods to minimize phase segregation for optimal mechanical properties; condensation of alkoxysilane and imidization often proceed concurrently. The use of organic/inorganic phase cross-linkers consisting of both alkoxysilane and amine usually produces hybrids homogeneous at a molecular level. − When cross-linkers are not used, the resulting silica particle sizes range from 50 nm to 1−2 μm and increase with increasing silica loadings (to ≈50 wt % vs ≈20 wt % silica for OAPS/PMDA and OAPS/ODPA). − Table shows selected silica/polyimide hybrid systems with thermomechanical properties. − A representative clay/polyimide hybrid system is also included for comparison 2 Selected Silica/Polyimide Hybrid Systems with Thermomechanical Properties ref.anhydrideaminesilica sourcecross-linkerhybrid structure (max.…”

Section: Resultsmentioning

confidence: 99%

“…ODPA/ODA imide (0 mol % OAPS) was prepared separately following traditional methods, − which included preheating amic acid solutions before casting to increase the molecular weights to optimize properties. Thus, equimolar quantities of ODPA and ODA were dissolved together in 5 mL of N -methylpyrrolidinone (NMP) in 20-mL glass vials and preheated at ∼100 °C for 1 d. Film casting, curing, and retrieval from substrates were conducted as described above.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, imide cube nanocomposites are also likely to exhibit lower water uptake and thus less property degradation than organic polyimides. Furthermore, in comparison with polyimides hybridized via sol−gel methods − or reinforced with clays, − incorporating OAPS requires no additional process steps for hybridization.…”

Section: Introductionmentioning

confidence: 99%

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Organic/Inorganic Imide Nanocomposites from Aminophenylsilsesquioxanes

et al. 2003

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We present here part of an ongoing study on structure-processing-property relationships in cubic silsesquioxane (cube) nanocomposites. Here, we focus on imide nanocomposites prepared from octaaminophenylsilsesquioxane (OAPS) as a model nanobuilding block for rigid, high-temperature hybrid nanocomposite materials. OAPS units are linked NH 2 vertex to NH 2 vertex by reaction with various dianhydrides to form three-dimensional nanocomposites. The architecture of the organic tethers between vertices can be manipulated to optimize processability, rigidity, and thermomechanical properties. Studies were initiated using an extreme tether structure with zero flexibility prepared by solvent casting and then curing mixtures of OAPS with pyromellitic dianhydride (PMDA) at 330 °C. The resulting materials are extremely brittle, making thermomechanical property measurements quite difficult. Tether rigidity, length, and cross-link densities were then modified using reactions of OAPS with oxydiphthalic anhydride (ODPA) and diluting with oxydianiline (ODA) to adjust nanocomposite stiffness. FTIR and DMA of the OAPS/ODPA/ODA nanocomposites suggest that cure temperatures of >500 °C are necessary for optimal imidization. However, increasing the cross-link density alone by increasing OAPS loading without curing at high temperatures also significantly improves thermomechanical stabilities. DMA, TGA, and nanoindentation measurements show that macroscopic relaxation is eliminated completely at OAPS loadings of >60 mol % providing 5% mass loss at temperatures >570 °C and compressive moduli of ≈3.8 GPa.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Organic/Inorganic Imide Nanocomposites from Aminophenylsilsesquioxanes

et al. 2003

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“…The vibrations between 1000 and 1100 cm À1 confirmed that Si-O-Si network was present in PI hybrid films. 38,[42][43][44] Properties of the resulting PI films 22 However, the incorporation of OAPS or polysiloxane leads to a slight reduction in tensile strength as well as break elongation of samples B and C, most likely due to the lower molecular weight and poorer interactions of PI chains arising from the bulky structures and evident steric hindrance of OAPS and polysiloxane. Additionally, OAPS and polysiloxane consist of a great many Si-O bonds, which are less polar than imide rings, resulting in the increase of free volume of PI matrix and leading to poor interactions between the polymer chains; also, the interval between the PI chains may be increased.…”

Section: Ftir Characterization Of Prepared Pismentioning

confidence: 99%

Atomic oxygen resistance of polyimide/silicon hybrid thin films with different compositions and architectures

Lei

Pan

Qiao

et al. 2014

High Performance Polymers

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Silicon (Si)-containing polyimides (PIs) with superior atomic oxygen (AO) resistance are promising materials for space applications. Here, in this study, we present the synthesis and characterization of eight Si-containing PI thin films and evaluate their AO durability. The resulting PI films exhibited high thermal stability and preferable AO resistance but showed slightly reduced mechanical performance relative to pristine PI. The highest optical transparency at 550 nm was observed for PI/octaaminopropylsilsesquioxane, while the lowest value was observed for PI/silica (SiO2) hybrids. X-Ray photoelectron spectroscopic study suggested that the topmost surface of PI was degraded at the early stage and an SiO2 inert protective layer was finally formed on the surface of hybrid films after AO exposure. It is found that Si-containing units of higher oxidation states and with higher Si/O molar ratio are favorable to improve the AO resistance. Dispersion of Si at molecular level contributes to improving anti-AO property as well as optical transparency of the prepared films. The characterization of scanning electron microscopy indicated a continuous SiO2 protective layer was crucial to prevent AO from eroding the bulk matrix.

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“…Research groups all over the world are trying to develop low dielectric constant materials by incorporation of nanosized pores while retaining the core properties of the host matrix (Hedrick et al 2004;Mecerreyes et al 2001;Takeichi et al 2001). The combination of organic and inorganic materials in thin film form may help in achieving the desired dielectric constant values along with other necessary attributes, as they combine the advantages of both inorganic and the organic components (Ha et al 2008;Wu et al 2001;Tang et al 2007). The incorporation of tetraethoxysilane (TEOS) into the polyamic acid-a precursor to PI through blending has attracted great deal of interest for developing films with low dielectric constant by in situ generation of air filled silica domains within the PI matrix in nanometer regime at elevated temperature (Chen et al 2004;Chen and Iroh 1999).…”

Section: Introductionmentioning

confidence: 99%

Polyimide/tetraethoxysilane-based hybrid polyfilms for microelectronics application

Kurmvanshi

Patel

et al. 2012

Microsyst Technol

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Polyimide (PI) has been extensively investigated as matrix for blends in the search of novel materials for microelectronics and engineering. Tetraethoxysilane (TEOS) is used as precursor for inorganic/organic hybrid material. The processing of PI with TEOS in thin film form offers considerable advantages to the state-of-the art for developing low dielectric constant materials with improved mechanical and hygroscopic properties for microelectronics devices. Taking this into account, the TEOS was incorporated in polyamic acid-a precursor to the PI and a number of properties were evaluated for PI ? TEOS films with different concentrations of TEOS. The films prepared with 10 -3 -10 wt% concentration of TEOS exhibit good overall balance of processing behaviour. The 350°C cured PI ? TEOS films have shown lower dielectric constant with respect to PI. The lower dielectric constant of PI ? TEOS films, as determined by Dielectric Impedance Analyzer was attributed to the in situ generation of air containing silica domains derived from TEOS dispersed within the PI matrix in nano meter regime. FTIR analysis has confirmed the generation of silica while AFM analysis showed the distinct appearance of silica domains dispersed into the PI matrix. The mechanical properties were evaluated by Universal Testing Machine on PI and PI/TEOS films. The films with 10 -3 -1 wt% composition of TEOS showed enhancement in overall mechanical properties while higher concentration i.e. 5 and 10 wt% of TEOS containing PI showed deterioration with respect to pure PI. The water absorption isotherms were measured and their absorption behaviour was correlated with dielectric constant and associated morphology.

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Organic-inorganic hybrid materials. II. Chain mobility and stability of polysiloxaneimide-silica hybrids

Cited by 17 publications

References 29 publications

Organic/Inorganic Imide Nanocomposites from Aminophenylsilsesquioxanes

Organic/Inorganic Imide Nanocomposites from Aminophenylsilsesquioxanes

Atomic oxygen resistance of polyimide/silicon hybrid thin films with different compositions and architectures

Polyimide/tetraethoxysilane-based hybrid polyfilms for microelectronics application

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